Rebecca Chandler
@RebeccaChandle1
Medical Doctor, UMC
The article, “Reporting of Adverse Events in Published and Unpublished Studies of Health Care Interventions: A Systematic Review”, published in PLOS Medicine and written by Su Golder, Yoon K. Loke, Kath Wright, and Gill Norman, reviewed 28 studies that provided a comparison of information on AEs according to whether the study was published or unpublished.
The researchers found that fewer published studies reported information on AEs compared with unpublished studies; that both a lower number of AEs and a narrower range of named AEs are reported in published studies compared to unpublished studies; and that the inclusion of unpublished data in meta-analyses leads to more precise conclusions on harms.
The authors’ assessment was that there is a substantial amount of unpublished data on AEs which may be “hidden” from health- care providers and patients in the form of unpublished data. They suggest that it is not possible to have a complete understan- ding of the safety profile of an intervention at the time therapeutic decisions are made by physicians and patients.
An important limitation of the signal detection work that we do at UMC is the lack of “denominator data” when identifying potential safety concerns from spontaneous data. In other words, we are unable to estimate how frequently a specific adverse event occurs when it arises in the post-marketing period as we do not know how many people have taken the drug in question. It would be very interesting to investigate if those signals identified in early post-marketing use have been previously observed in clinical trials but not reported.
There is a growing movement calling for full disclosure and unrestricted access to clinical trial data, as exemplified in campaigns such as AllTrials. Given the potential for unpublished data to be an important source of information on harm from medicines, UMC fully supports the authors’ call for a new policy and action to make adverse event data readily accessible to the public.
Read more:
- Golder, S., et al, "Reporting of Adverse Events in Published and Unpublished Studies of Health Care Interventions: A Systematic Review", PLOS Medicine, 2016.
